There were 22 companies testing autonomous vehicles in California as of February 2017, and Uber began offering autonomous vehicle rides, with a backup driver, in Pittsburgh last October.

Ford has announced plans to have a “high-volume, fully automated” autonomous vehicle commercially available by 2021 through a ride-sharing service. The vehicle will not have a steering wheel or pedals.

“Full autonomy is really just around the corner. It’s all the more amazing when you think about all the various hurdles that still have to be overcome between now and that point in time,” says Ed Kim, vice president of industry analysis for the automotive research firm AutoPacific.

A new report suggests that states will need to take the lead in dealing with the traffic and safety issues that will arise when autonomous and driver-operated vehicles start sharing the roads. The Governors Highway Safety Association issued the report in February. As of today, no state has enacted a law prohibiting autonomous vehicle testing or operations, and self-driving cars can operate legally in most, if not all states without any explicit authorizing legislation, according to the report.

One of the key challenges is how drivers of more traditional cars will react when they’re sharing the roads with autonomous vehicles, says Kara Macek, spokeswoman for the GHSA.

For example if autonomous vehicles are following the speed limit, will human drivers become aggressive around those vehicles? Research shows that they could, Macek says.

“Should they be programmed to break the law? We don’t have the answers, just the questions,” she says.

Another key takeaway from the report is the recommendation that states don’t rush to into passing laws or establishing regulations regarding issues related to autonomous vehicles.

“We’re really looking for model state laws to be developed and help states navigate so we don’t end up with a patchwork of inconsistency in this country,” Macek says. “So we’re looking to the federal government on some of those issues, in terms of establishing coordinated policies and practices.”

For several years, many cars have featured Level 1 autonomy, which includes features like cruise control and lane guidance. Newer models feature Level 2 autonomy, defined as occasional self-driving in which the vehicle can take control of speed and lane positions in certain situations. Tesla’s Autopilot software would be one example.

There’s broad consensus that Level 3 to 5 autonomous vehicles will be commercially available within five years and could be operating on the road if appropriate laws and regulations are in place, according to the report. The self-driving car that Ford plans to release in 2021 would be a Level 4 autonomous vehicle.

“Other drivers may not realize that the vehicle next to him has the ability to make some basic driving decisions for the human driver,” says Ian Grossman, Vice President of Member Services and Public Affairs.

Grossman says it will become increasingly important for drivers to understand the capabilities of automated vehicles as the technology emerges. Whether you own one or are sharing the road with one, drivers need to learn how automated vehicles will react and respond in everyday and unusual circumstances.

There are still issues to resolve in terms of how to get infrastructure up and running to be able to support autonomous vehicles.

For example, many parts of the country still have broken roads, poorly marked lines and things of that nature. Then there are also considerations about things who would be liable — the rider or the automaker — if an autonomous car gets into an accident.

“There are still a lot of open question marks and things that need to be done before full autonomy is here, but make no mistake it’s coming here very soon,” Kim says.